I. Field
The present disclosure relates generally to communication, and more specifically to techniques for sending and receiving acknowledgement (ACK) information in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, etc. These wireless systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
In a wireless communication system, a base station may transmit data to a user equipment (UE) on the downlink and/or receive data from the UE on the uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station. The UE may send channel quality indicator (CQI) information indicative of the downlink channel quality to the base station. The base station may select a rate or transport format based on the CQI information and may send data at the selected rate or transport format to the UE. The UE may send ACK information for data received from the base station. The base station may determine whether to retransmit pending data or to transmit new data to the UE based on the ACK information. It is desirable to reliably send and receive the ACK information in order to achieve good performance.